Zearalenone

Zearalenone, a phytoestrogenic mycotoxin usually produced by Fusarium species, is shown to be a cytotoxic compound, but alos binds to the estrogen receptor (ER) (IC₅₀ values are 166 and 240 nM for ERβ and ERα respectively) and was found to stimulate the transcriptional activity of both subtypes at concentrations between 1 - 10 nM. This agent has demonstrated the ability to induce apoptosis via activation of mitochondrial release of Cytochrome c, production of reactive oxygen species (ROS), activation of caspase-3 and caspase-8, and induction of endoplasmic reticulum stress. Additional studies suggest that Zearalenone also up-regulates Bax expression and down-regulates Bcl-xL expression in cells, which also contribute to a halt in cell proliferation. The cell growth arrests caused by this mycotoxin seem to take place during the G₁ phase of the cell cycle.